1. Field of the Invention
The present invention relates to a thermally released separation or disconnecting device, particularly for fire protection systems. The separation device includes two oppositely arranged joining members which are connected to each other and are subjected to a tensile force. A destructible thermal release element is held between the joining members.
2. Description of the Related Art
Separation devices of the above-described type are arranged between two ropes or similar pull elements, so that the stirrup-shaped joining members thereof are under tensile stress. The devices are used, for examples, in fire extinguishing devices or opening and closing devices, which trigger a safety function when a certain temperature is exceeded, for example, open or close valves, open smoke outlet flaps and closing flaps in ventilation ducts.
The present invention is directed to a separation device as it is disclosed, for example, in German patent application 1 559 693. In that separation device, the release element is formed by a thermally released glass bulb or ampul. When a certain temperature is exceeded, this glass bulb is destroyed and releases the separation device, i.e., the stirrup-shaped joining members can move apart from each other in order to trigger the appropriate safety measure. The tensile forces, which act on the joining members and, thus, may be transmitted more or less to the glass bulb, may be relatively great. In the separation device according to German patent application 1 559 693, the force parallelogram formed by the joining members acts in such a way that only a compressive force is transmitted to the glass bulb. Because of the unfavorable arrangement within the parallelogram, this compressive force is even greater than the tensile force. This is not acceptable in many cases. The glass bulb must be constructed with an appropriately high strength which, in turn, impairs the response sensibility. Modern glass bulbs are slender and respond much more quickly. For this reason, it is advantageous to reduce the compressive forces and to utilize the slender, quickly responding glass bulb. Because of their high reliability, glass bulbs have been found very useful as thermal release elements in sprinklers.